Process of drying and seasoning wood.



B. LOOMIFJ,

PROCESS OF DRYING AND SEASONING WOOD.

APPLICATION FILED JUNES, 1909.

Lafiflgma Patented Jan. 14, 1913.

311mm for UTTED STATES PAT I. Fro.

BURDETT LOOMIS, OF HARTFORD, CONNECTICUT, ASSIGNOR TO LOOMIS UTILIZATION COMPANY, A CORPORATION OF NEW JERSEY.

PROCESS OF DRYING AND SEASONING WOOD.

Application filed June 3, 1909. Serial-No. 499.960.

To all whom it may concern:

Be it known that I, BUnnE'r'r LOOMIS, a citizen of the United States, residing at Hart-ford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Processes of Drying and Seasoning lVood, of which the following is a specification.

This invention relates to the process of drying and seasoning wood to prepare it for the market or for subsequent treatment with preservatives, or with fireproofing or coloring solutions.

The object of my invention is to providev for thoroughlyand uniformly drying and seasoning wood from the surface to center without checking'or cracking or formation of hard crusts or shells near the surface of the wood.

I have discovered that, by the alternate operations of gradually heating wood by hot gas or products of combustion in a .closed chamber and then gradually cooling the same by the gradual admission and circulation of cold gas or air, repeated as often as necessary, depending upon the size and kind of wood treated, the moisture will be expelled from the interior of the wood, and the operation of seasoning and drying perfectly effected without formation of hard crusts near the surface and without checking or cracking, resulting in the production of superior lumber, adapted directly for various uses, and particularly for subsequent treatment with preserving, fire-proofing or coloring solutions.

The matter constituting my invention will be defined in the claims.

I will now fully describe my invention with reference to the accompanying drawings which illustrate suitable apparatus for carrying out the process and in which- Figure 1 represents a vertical lon itudinal section of a tank and connections fbr treating comparatively small pieces of wood. Fig. 2 represents a similar section of a long tank for treating poles or other long heavy timber.

Referring now to Fig. 1, the treating tank A is madeof metal or concrete and is provided with a tight fitting cover a which ma .be connected by ropes or chains with a tro Specification of Letters Patent.

Patented Jan. 14, 1913.

placed in a cage C which is preferably provided at the top with a link which is connected by a rope or chain c with a trolley device 0. The trolley may be provided with a winding drum for raising and lowering the cage.

\Vith the lower part of tank A, or at any desired height in the wall, I connect a combustion chamber D, having an air inlet pipe (Z for admitting an excess of air, and a gas inlet pipe d, for admitting an excess of gas when required from the holder. A steam supply pipe 5 connects with pipe d for supplying steam, if required, to tank A. With the outer end of this combustion chamber connects a burner E having a gas supply pipe cl and 6 preferably connect with a main gas pipe Z leading from a holder L and such pipes are provided with valves as shown. A circulating pipe F may connect with the bottom of tank A, or at othersuitable points, and also with the combustion chamber D, and is provided with a valve f. A drip or discharge pipe H, having avalve it, connects'with pipe F and leads to a condenser K, and a pipe connects the condenser with the holder L. A by-passpipe' is, provided with a valve, connects with pipe H and, passing around the condenser, connects with pipe ]c leading into the holder. By this arrangement of pipes tar-water and vapor may be passed off through pipe H to the condenser, or gas may be passed through pipe H and by-pass pipe 70' directly into the holder, so that gas may be circulated from tank A into the holder and' thence back through pipe (Z' into the tank. All pipes will be provided with valves where required for successfully conducting the operation. v

A circulating pump N is connected in pipe F, by means of which a gaseous mixture will be more effectively drawn off from the treating tank A and caused to circulate through chamber D back into contact with the wood in the treating tank, or through the condenser, the holder and pipe d back into the treating tank for cooling down the heated charge.

Referring now to Fig. 2, the treating tank is in the form of a long cylinder A provided with removable heads a" and with a long heavy timber.

' nozzle may be connected tangentially to chamber D for discharging the flame and products at a sharp angle against the wall and cause them to circulate around in the chamber before escaping through the perforated top plate. A pipe I) for admitting cold air and a pipe b for admitting cold gas connect with combustion chamber D.

'Gas and vapor circulating pipes F, hav

ing valves f, preferably connect with the ends of cylinder A and with the combustion chamber D' Drip or discharge pipes H, having valves h, connect with pipes F and may lead to a condenser K or directly to a gas holder. These pipes serve for carrying ofi an excess of gas or vapor and returning it to the holder or for discharging tar-water or other liquid material expelled from the wood. A pressure gage m and a thermometer n may be applied to tank A for indicating the pressure and temperature in the tank.

The process may be conducted substantially as follows: The cage C, being filled with loosely laid boards or other form of lumber, is lowered into the tank and the cover a tightly closed in any convenient manner. The holder L is preferably supplied with a mixture of producer-gas and water-gas, but other kinds of gas may be used. he holder may be supplied with natural gas where available. Gas and air are admitted" to the burner through pipes e and e and ignited and burned in the combustion chamber D. A small flame will at first be produced and gradually increased for gradually heating the wood in tank A. This heating may be continued for a period of one to six hours according to the size and character of they wood under treatment. The temperature will 'be gradually increased up to about 300 Fahrenheit. The range of temperature, however, will be greatly varied, according to whether the wood is comparatively dry or green. If the .wood is comparatively dry, moisture in the form of steam may be admitted to the combustion chamber through pipes s, and d, and the heat may be moderated and controlled by supplying cold gas through pipe d' to prevent too rapid heatin and checking or cracking of the woo The material having been heated through to the desired temperature, not high enough to oa -lei expelled from the wood.

injure the fiber, the tank and body of the wood is gradually cooled down by reducing the flame at the burner and gradually admitting cold air through pipe (Z or cold gas through pipeal. Preferably, cold gas is admitted and mixed with products of combustion for gradually reducing the temperature so as not to suddenly contract .the wood. If this operation of cooling is conducted gradually in an atmosphere of gas and products of combustion, the internal moisture in the heated wood will pass freely out through the surface and thus be If the temperature is too quickly reduced, the wood near the. surface will become contracted and hardened or filled with crust, so that the internal moisture cannot get out. By gradually reducing the temperature, the internal heat drives out the moisture. At the same time, the cold gas or mixture of gas and air circulating'in contact with the wood, takes up the moisture and carries it away. In this way the temperature is reduced to normal or about 60 F. This cooling operation may be conducted from one to six hours, according to the size and character of the wood under treatment. The wood having been cooled down and partially dried, I now commence heating again, gradually raising the temperature to the revious high degree. After a suitable time, when the wood has been thoroughly heated through, I again cool off the contents of the tank by means of cold gas and air or a mixture of the same circulated in the treating tank. Tn this way the internal moisture will be expelled from the wood and carried ofi' by the circulating cooled gas. By using products of combustion with the con: tained moisture and carbonic acid, 1 prevent the formation of crusts or hard deposits in or near the outer surface of the wood. In both heating operations no crust or extra dried surface is formed. The heat can, therefore, at all times, easily penetrate to the central portion of the wood and the moisture and air at all times pass out from the wood and be carried away by the gas.

It is to be noted that the hydrogen in water gas or producer gas, when burned with oxygen, produces water, so that the products of combustion are moist. If neces- 'sary, extra moisture is added in the form of above described apparatus my process of gradually heating the woodin treating tank A by means of the circulating hot gaseous products, and then gradually cooling the wood for drawing out the moisture and carrying it ofl through circulating pipes to a condenser is conducted at substantially the ordinary atmospheric pressure in the treating tank. In practice I find that no pressure is required in heating a charge of wood by circulating in contact therewith hot gases or products of combustion, and in fact I obtain more satisfactory results by using a circulating pumpwhich will draw off and cause circulation of the gases at or below the ordinary atmospheric pressure.

After the wood'has been thoroughly dried and seasoned by the alternate gradual heating and the gradual cooling, repeated as often as necessary, the cold gas and air are shut ofi and there is admitted to the treating tank a supply of hot dry gas, which is passed over and in contact with the wood, thereby forming on or in its surface, a crust or hard dry shell which will prevent subsequent absorption of moisture by the dry seasoned wood.

After the wood has been dried and sea soned by my process, it will readily take up and absorb a preserving or fire proofing solution and can be readily'stained or colored throughout its entire body. Wood can thus be stained or colored through and through so as to retain any desired coloring.

\Vith some kinds of wood the alternate heating and cooling in an atmosphere of .and conducting off the moisture by circulating in contact therewith a cool gaseous or aeriform mixture, thereby drawing moisture to the surface of the wood and carrying it off, and repeating the operations until rying and seasoning are effected.

2. The rocess of drying and seasoning wood, which consists in heating it in a closed chamber by circulating in contact therewith, hot gaseous products, then gradually cooling it by circulating in contact therewith a cool gaseous or aeriform mixture, for expelling moisture from interior. of the wood and carrying of]? the moisture, whereby the premature formation of exterior crusts and cracking are prevented.

3. The process of drying and seasoning wood, which consists in burning gas with air and circulating the resulting products in contact with the wood, thereby gradually heating it, then gradually cooling the wood by circulating in contact therewith a cool gaseous or aeriform mixture, carrying off the moisture and repeating the heating and cooling operations till the wood is thoroughly dried and seasoned without cracking or checking.

4:. The process of drying and seasoning wood, which consists in alternately heating it in an atmosphere of hot gas or gaseous products, and cooling it in an atmosphere of cool gaseous or aeriform mixture, and after thoroughly drying, subjecting the wood to hot dry gas to form an exterior crust or hard dryshell for preventing the subsequent absorption of moisture.

5. In the process of drying and seasoning wood by subjecting it alternately to hot and cold gaseous products till dried throughout its body, the step or operation of forming an exterior crust or hard shell by subjecting the dry'wood to the action of hot dry gas, to prevent the subsequent absorption of moisture.

In testimony whereof I afiix my signature in presence of two witnesses.

BURDETT LOOMIS.

Witnesses:

JAMES L. CRowLEY, ALBERT H. PITKIN. 

